on end not triggred on aws lamda

[JogiPrasadPakki]

I am want take video thumbnail on lamda but "end" event not triggered on lamda but working on my windows local machine i set all ffmpeg environment variable on lamda this is my code

 new ffmpeg({ source: target',nolog: true })
 	.on('error', function(err) {
	    console.log('An error occurred: ' + err.message);
	  })
 	.on('filenames', function(filenames) {
	    //console.log('Will generate ' + filenames.join(', '))

	    console.log(filenames[0])

	  })
	  .on('end', function() {
	  	console.log('Screen shots taken')
	  })
    .takeScreenshots({ 
    	count: 1, 
    	timemarks: [ '00:00:02.000' ], 
    	size: '1280x720'}, 
    	'/tmp/')